Maps are a vital part of location based services; they are used in both the creation and consumption of these services and applications. For example, mediascapes generally use maps in their creation and consumption. Mediascapes are collections of digital media items linked to the physical world through action-triggers. Each action-trigger specifies a condition set of one or more conditions concerning the physical world, and at least one media-item-specific action that is to be triggered upon satisfaction of the condition set. A typical condition would be a location-based condition satisfied upon a user entering a specified geographic zone specified at creation time via a map. The action-triggers are typically specified in a script which is downloaded, along with the related media items to a user-portable device such as a hand-held computer or PDA (Personal Digital Assistant). The user device interprets inputs in accordance with the script to carry out specified media actions on particular ones of the stored media items. For example, a simple script might specify a location-based action-trigger that causes the user device is to play a particular audio file whenever the user enters a particular city square as determined by a positioning system such as GPS.
Obtaining accurately aligned maps of an area for the creation of mediascapes and other location based applications is a major obstacle to the widespread deployment of such applications by community groups and other small and medium organizations. The existing ways of sourcing accurate maps for location based applications all have drawbacks:                Using map imagery and coordinate data from online or printed maps almost always involves copyright issues with licenses generally only being available on very restricted terms. Additionally, such maps are often far from ideal for authoring or experiencing location based applications.        Purchasing mapping data from the original source of the data. This is possible but tends to be prohibitively expensive for most authors and consumers. Again, usage terms are usually very restrictive.        Making maps oneself or using a map supplied without coordinate data and then aligning the map by hand using GPS readings calls for mathematical abilities that are beyond most authors, as well as being time consuming and prone to errors.        